Field of the Invention
The present invention generally relates to apparatuses for measuring the concentration of chlorine dioxide gas in an enclosed space, and particularly relates to a chlorine dioxide gas concentration measuring apparatus which uses ultraviolet light.
Description of the Related Art
Chlorine dioxide gas is effective in performing disinfection or fumigation in an enclosed space, and is most effective in performing disinfection in factories that produce food or medicine, for example, and which require that a hygienic environment be maintained. The applicant has made various proposals concerning chlorine dioxide gas generating apparatuses capable of generating such chlorine dioxide gas directly inside factories etc.
Since improper handling of chlorine dioxide gas can cause hazards such as explosions, it is of the utmost importance to ensure that it is possible to adjust and manage the gas concentration in the gas generating apparatus and after generating the gas, depending on the usage conditions. To that end there has been proposed, for example in Japanese Unexamined Patent Application Publication No. 1979-10784, an apparatus for measuring chlorine dioxide gas concentration as a “bleaching compound” in the pulp and paper industry.
Measuring and managing the concentration of chlorine dioxide gas is also important when performing disinfection, and the concentration of gas needs to be measured and managed both during disinfection, and for confirming safety afterwards. In addition, measuring and management of chlorine dioxide gas concentration must be performed in real-time, in order to prevent the occurrence of any unforeseen consequences (such as the aforementioned explosive hazard or adverse effects on personnel) during disinfection.
As discussed in Japanese Unexamined Patent Application Publication No. 1998-311790, chlorine dioxide gas is very toxic, corrosive, and can strongly irritate mucous membranes and the eyes, and has a very low TLV-STEL (threshold limit value-short time exposure) of 0.3 ppm (ml/m3), as defined by the ACGIH (American Conference of Governmental Industrial Hygienists) in 1993 to 1994. It is therefore important to measure the concentration of chlorine dioxide gas in order to avoid the aforementioned adverse effects, and to comply with the threshold limit value of the work environment. Japanese Unexamined Patent Application Publication No. 1998-311790 proposes a chlorine dioxide gas measuring apparatus for this purpose.
The contents of Japanese Unexamined Patent Application Publication No. 1979-10784 and Japanese Unexamined Patent Application Publication No. 1998-311790 are incorporated herein by reference in their entirety.